Studies have investigated the efficacy of alpha-GPC for cognitive disorders including stroke and Alzheimer's disease. An Italian multicentre clinical trial on 2,044 patients suffering from recent stroke were supplied alpha-GPC in doses of 1,000 mg/day for 28 days and 400 mg three times per day for the five ensuing months. The trial confirmed the therapeutic role of alpha-GPC on the cognitive recovery of patients based on four measurement scales, three of which reached statistical significance. Commonly used doses are 300 to 1,200 mg daily.
Industrially, alpha-GPC is produced by the chemical or enzymatic deacylation of phosphatidylcholine enriched soya phospholipids followed by chromatographic purification. Alpha-GPC may also be derived in small amounts from highly purified soy lecithin.
Many users report degradation of alpha-GPC when stored openly or for long periods of time. Alpha-GPC is hygroscopic and will pull moisture in from the surrounding air. This will cause the powder to turn into what appears to be a gel. Alpha-GPC with >99% purity will undergo this process at a visible rate (seconds to minutes) and thus requires minimized exposure to the air. This hygroscopic quality can cause gel capsules not fully packed with alpha-GPC to dissolve. Proper storage methods need to be used with alpha-GPC and include removing all air from the container, double bagging with plastic bags rated for chemicals (less likely to leak air), and storing bulk/excess inside the freezer. Vacuum sealed bags are highly recommended. For people accessing alpha-GPC daily it is advisable to separate a month's supply from excess and storing the excess as best as possible. Vacuum sealing a large supply into many 1 month dividends is a method positively reported by many users. It is important to note that hygroscopy is not degradation and leaves the substance still usable, however, the ability to accurately weigh a dose is no longer possible as the substance being weighed will be a mixture of powder and water. Liquefied or gelled alpha-GPC may also be indicative of poor storage and thus have an increased likelihood of actual degradation.
^ abParnetti, Lucilla et al. (2007). "Cholinergic precursors in the treatment of cognitive impairment of vascular origin: Ineffective approaches or need for re-evaluation?". Journal of the Neurological Sciences257 (1–2): 264–9. doi:10.1016/j.jns.2007.01.043. PMID17331541.
^Barbagallo Sangiorgi, G; Barbagallo, M; Giordano, M; Meli, M; Panzarasa, R (1994). "Alpha-Glycerophosphocholine in the mental recovery of cerebral ischemic attacks. An Italian multicenter clinical trial". Ann NY Acad Sci717: 253–69. PMID8030842.